A man identifying himself as a Japanese hostage told Al Jazeera that he and a Norwegian hostage had been wounded by Algerian sniper fire. A French national told France24 that the hostages have been forced to wear explosive belts and that the militants are heavily armed.

The U.S. is largely in the dark despite sending a quick response force to the area on Wednesday night. A senior U.S. official told Raddatz around 09:00 EST that they're "trying to get clarity but just don't know anything for sure."

CBS News national security correspondent David Martin reports that a U.S. drone has arrived over the Algerian gas plant, "giving the U.S. its first look at what is happening."

The hostage situation began on Wednesday when at least 20 jihadists raided the In Amenas oil field 60 miles away from the Algeria-Libya border, killing two foreigners and kidnapping between 20 and 41 foreign hostages from countries including the U.S., UK, France, Romania, Ireland, Malaysia, Japan and Norway.